Objectives/Scope: Pre-tensioned Pipeline Bundles (towed pipeline production systems) unlock HP/HTrnfields by making them economically feasible and technologically possible. Analysis shows pre-tensioningrnallows HP/HT Bundles to be designed to operate at 220°C & 1379 bar without the need for globalrnbuckling mitigation, rock dump, buckle initiators, expansion spools, cooling spools, HIPPS, etc. and hencernprovide a cost-effective fully integrated HP/HT solution. The pipeline Bundle product has matured (overrn35 years, with more than 75 installed to date) to the upper pressure and temperature limits of 604 bar andrn160 °C respectively, as realised on the Total E&P UK West Franklin Project. This paper presents thernresults of the FEA and elaborates the testing program planned at the Subsea 7’s Wester Pipelinernfabrication facility, North East of Scotland, on a Bundle pipe in pipe section approximately 170m usingrna jacking system to introduce pretension and then heated to 220 °C with one end fixed.rnMethods, Procedures, Process: A fibre optic monitoring system will be used in conjunction withrnstrain gauges to monitor axial, hoop and temperature strains respectively on the production and sleevernpipes. These strains will then be compared with the results of the FEA simulation as part of the verificationrnprocess. The simulation models the effects of thermal expansion, pre-tension, centraliser friction, impactrnof compression on subsequent loading cycles and pressure.rnResults, Observations, Conclusions: At high pressure and temperature operational conditions, thernresults show that pre-tensioning introduces significantly lower compressive forces in the production pipernas well as lower tensile forces in the sleeve pipe. This allows stress based design within the linear elasticrnregion, thereby allowing associated design advantages and cost reduction for certain HP/HT conditionsrnstrain based criteria can be employed while still avoiding ECA. The FEA simulation model and approachrnis shown to accurately predict the behaviour of the pre-tensioned pipeline Bundle system for future HP/HTrnprojects.rnNovel/Additive Information: Pre-tensioned Bundles enable fluid transport at 220 ℃ and pressures uprnto 1379 bar and reduce cost of design, build, test and operation phases by mitigating the need to usernHIPPS, expansion spools and cooling spools for each HP/HT tie back individually.
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